Sewing machine



OA STROBEL Y SEWING MACHINE May 2, 1939.

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41a 4s b9 40 o. STROBL SEWING MACHIN May 2, 1939.

Filed March 25, 1937 9 sheets-sheef Inventor May 2, 1959` o. sTRoBEL Y 2,157,032

'SEWING MACHINE /Fil'edurh 25, 1957 9 sheets-sheet 4 71o. 'ma

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SEWING MACHINE Filed March 25, 1937 9 Sheets-Sheet 5 Inventor Der w fz ttorner.

May 2, 1939. 0h STROBEL 2,157,032,

I SEWING MACHINE Filed March 25, 1937 9 Sheets-Sheet 6 X A 20 @HJ v Invenb v 1 Der Attorn O. STROBEL SEWING MACHINE May '2, 1939.

Filed March 25, 1937 9 Sheets-Sheet 7 Inventor O. STROBEL SEWING MACHINE May 2, i939.

Filed March 25, 1937 9 Sheets-Sheet 8 O. STROBEL.

SEWING MACHINE 9 sheets-shawl@ Filed March 25, 1937 attorney Patented: May .2,.11939- i Oskarstrobel, Munich, Germany Application "March 25, 1937, Serial No. 132,929 In VGermany December 3, 1935 s lClaims. (ci. liz-17e) lAnother object of this invention is to provide means forfeliminating further disadvantages in- 'I'he present invention relates to a new andimproved sewing machine, :more particularly to a sewing machineof `the'lllind-stitch type by means of Vwhicha plurality of L-layers lof material can`be sewn together. The stitches baste one of the layers'at a predetermined spacing, whereby the iinished job-appears to be hand-stitched, or' for any other purposes suchas, vfor example, are accomplis'hed bythe I.machines-'disclosed in the U. S. Patents No. 1,926,644 and No. 1,9641381.

An object of the `presentinvention resides in the `provision of improvements in .sewing machines for making spaced blind stitches, `particularly in the provision .of =means1for improving the sewing together of layers :of material of vany thickness correctly, quickly, and reliably.

With sewing machines of the kindfdescribed in the U. S. Patent No.1,926,`644, sewing together of layers ofimaterial-of equal or almost equal thickness only is possible. 'Ihereason for this'is that, in said'machine-thestroke of the device for bending'the material to'be'sewn is always the same, whereas the :part on which vthe material `rests .makes'a stroke whichis alternately long andV short withoutvariation, however, of thev difference or the vinterval between the long `and the short stroke.

A further disadvantage of the interval l'sewing machine ofthe kind 'disclosed'in U. S. PatentNo. 1,926,644 is that,'for moving-'the support'forthe material upwards and downwards, comparatively large masses'mustbe moved, wherebyyibrations are caused which impair exactness and reliability of operation and reduce the 'operating speed.

It is an object of the present "invention tovprovide means. for'varyingthe interval betweennthe short andthe long stroke of the 'support of the material tobe-sewnythis variation or adjustment can be madeby the person operating -thesewing machine, van'cl..no.special expert is required for making the adjustment, y

Adjustment of thedifferencebetween the long and'short strokes is necessary wheneither two thick layers of cloth or twothin layers orlayers of cloth of medium thickness or a `thickand a thin material are to `be sewn together in the interval. The'differenceb'etween the strokes of the material carrier can be exactly adjusted to suit the thicknessfof the material to be worked, and a good interval'seam can be created.

Toaccomplish the abovestated objects, a machine as disclosed inithe'U. S..Patent No. 1,926,644 hasbeen provided with-meansfwhich will be de scribedlater on and which form part ofthe present invention.

vherent to an interval stitching machine of the type-disclosed in the U. S. Patent No. 1,926,644.

The movement of the material to be sewn together with the motions of the carrier of said material and of the device for bending the material annoys the operator and causes damage to the material'to berworked. These disadvantages are particularly noticeable when thick and heavy material and pieces of great size are to be worked. The main disadvantage, however, is that in this case comparatively large masses are in motion which cause undesired vibrations which do not permit fast operation o f the sewing machine. Whereas with the known interval sewing machines the device for bending the material, carries out a swinging motion of always the same amplitude and the material to be worked makes al ways the same stroke, the present invention has for its object the provision of means for' varying vthe diilerence or the so-called interval of the strokes of the node forming element,"\ whereby this variation can be carried outat will by the operator of the'machine.

Due'to the adjustability of the movements of the node forming element, cloths of equal thickness or-of different thickness, for example, a very heavy and a very thin clothvas well as cloth of blind stitches in the interval.

.medium thickness can be sewn together with The adjustment of the difference of the strokes of the node forming element to suit variable thickness of the cloth to'be Worked is extremely easy and requires very little time.

In all cases, a correct, flexible, soft, and loose interval seam is created which is otherwise only possible with stitching by hand.

Interval sewing machines according to the present invention are particularly suitable for iitting the lining in coats and frocks.in such a manner that the seam can be seen neither from the outside nor from the inside.

embodiment of my invention.

In the drawings attached to the present speciiication, various modifications of the present invention are illustrated.

In the drawings:

' Fig. 1 is a top view of a sewing machine according to the present invention.

Fig. 2 is'a side view of a machine according to the present 'invention taken along line 2--2 in Fig. 1.

Fig. 3 is a sectional View on the line 3-3 of Fig. 1.

Fig. 4 is a sectional view on the line 4-4 of Fig. 3.

Fig. 5 is an enlarged detail section of the means for regulating the downward turning of the pivoted work-arm. n

Fig. 6 is a sectional view on the line 6-6 of Fig. 5.

Fig. 7 is a sectional view on the line' 1-1 of Fig. 1.

Fig. 8 is a sectionalview on the line 8--8 of Fig. 7.

Fig. 9 is a sectional view on the line 9 9 of Fig. 7.

Fig. 10 is a detail elevation partially in section, showing how the needle is passed through all the layers of the piece of cloth.

Fig. 11 is a view similar to Fig. 10, showing how the needle is passed through a portion'of the layers of cloth.

Fig. 12 is a sectional view illustrating the needl plate, showing the details illustrated in Fig. 10.

' Fig. 13 is valongitudinal sectional view showing the details illustrated in Fig. 11.

Fig. 14 shows in larger scale part of the lower part of Fig. 7.

Fig. l5 illustrates a section taken along line I5VI5in Fig. 14.

Fig. 16 is a longitudinal part sectional view of a modified blind stitch sewing machine according to the present invention.

Fig. 17 is a front view of the stitch plate with the node forming element of the machine illustrated in Fig. 16.

Fig. 18 illustrates the` rear part of the machine shown in Figs. 16 and 17.

Fig. 19 is a view of the rear part shown in Fig. 18 and taken in the direction of arrow I9 in Fig. 18.

Fig. 20 is a large scale part sectional view of the drive for the device for bending the material, said View being taken along line 20-20 in Fig. 21.

Fig. 21 is a sectional view of the device illustrated in Fig. 20 and taken along line 2I-2I of that gure.

Fig. 22 is a large scale view of a modification o-f the drive for the device for bending the material.

Fig. 23 is a sectional view of the device illustrated in Fig. 22 and taken along line 2323 of that figure.

Fig. 24 is a large scale view of another modification of the drive for the device for bending the material. i

Fig. 25 is agsectional view of the device illustrated in Fig'. 24 and taken along line 25-25 of that figure.

The invention is illustrated in connection with a blindstitch machine which is mainly standard in construction. This machine has a frame F,

la main shaft I, a drive pulley 2, and the usual hand-wheel 3. It is also provided with the usual pivoted work holder 4 which is pivotally connected at 5 to the frame F of the machine. The machine is also provided with the usual thread guide 6 having the usual spring 1 and the usual regulating member 8.

dog and the looper and the needle by means of said standard connections which are shown in Figs. 1 and 2.

For example, the machine comprises a feed dog bar 9 which is connected to the main shaft by means of a suitable eccentric I0. Likewise, the

which turns in unison with the" drive shaft.

The main shaft I actuates the feedv machine is provided with a looper II of standard construction which is connected to a looper bar I2, and this looper bar I2 is connected by means of a ball-bearing to the usual turnable yoke I4 which is pivotally connected to the frame of the machine at I5. The looper bar I2 is provided with the usual yoke IB which is connected by means of the usual universal joint to the inclined. projection vI1 which extends,l from the collar I8 The needle Nis mounted by means of a needle bar Na upon the usual shaft 2D which is suitably connected to the main drive shaft I so that the needle shaft 20 is caused to oscillate in the usual manner. The Work-holder 4 is provided with the usual pair of pivoted fingers 80 and 8| on which the work is sup-ported, and the work-holder is also provided with the usual finger 22 which is lcaused to turn up and down in order to form the bight in the llayers of cloth. The fingers 80 and 8| have extensions 80h to which the tension springs 88a and 8Ia are connected. 'Ihe members 80 and 8l are pivotally connected to the i work-holder in the usual manner.

The machine has the usual presser foot 23. l

This presser foot 23 is fixed in the usual manner to the frame arm 24.

The Work-holder 4 is automatically depressed at each alternate stroke of the needle or in any other desired ratio. 'I'he drive shaft I is located in a frame arm 25. It is to be understood that,v when I refer to the work-holder, I refer to the support 4 which is shown in Fig. 4. When I specify the work-holder, I do not intend to refer merely to the rib 22 which forms the fold or bight in the material. The rib or finger 22 is always operated in the usual manner, so that it is adjusted or shifted in unison with the automatic shift of the member 4.

As shown in Fig. 5, the main drive shaft I has freely mounted thereon a collar or sleeve 26 which has an eccentric portion 26a and a concentric portion 26h. Although the parts 26a and 26h are integral, they may be considered as forming separate operating members. The eccentric member 26a has the usual eccentric strap 21 mounted thereon, and this strap 21 is integral with a lever 28.

As shown in'Fig. this lever 28 is pivotally connected at 29 to a member 30 which is clamped or otherwise suitably secured around the shaft 3| upon which the rib 22 is mounted, solthat the rib 22 is caused to oscillate. Any other form of rib may be used to form the fold in the fabric in order to permit the formation of blind-stitches.

The concentric part 2Gb of the collar 26 has a gear 32 keyed thereto. `One side of this gear 32 either-k has integral therewith or suitably connected thereto a ring 33. A pair of vertically movable arms 34 and 35 are.provided which arms have a rectangular, preferably square upper part. These arms 34 and 35 are also'provided with openings through which the member 2Gb passes, and these openings are square and slightly greater than the sleeve 2Gb, so that the arms 34 and 35 can be vertically shifted With'respect to the member 2Gb. The arm 34 has located therein a guide block 34a which fits upon the sleeve 2617, and the arm is provided with an inner guide block 35a which fits upon the sleeve 26h. The guide blocks 34a and 35a also have outer .peripheries which are rectangular and preferably square, and they have circular openings through which the sleeve 2Gb passes. The inner surfaces of armsv 34 and yao 2,1tr,os:sv 35 slide on the outer surfaces of guide blocks 34a Y and 35a.

As shown in Fig. 3, thereccentric member 26a abuts a portion of the internal surface of the frame arm 25. The assembly of the parts is maintained by the laterally projecting flange'of the sleeve 26 and by means of a collar 36 which is clamped to the shaft by means of a screw 31. The collar 36 is provided with a pair of lugs 38 and 38a which fit into corresponding depressions provided in the sleeve 26h, so that the sleeve 2Gb turns in unison with the shaft Likewise, the gear 32 is also caused to turn in unison with the shaft because the gear 32 is keyed to the sleeve 26h. When the shaft turns, the guide blocks 34a and 35a do not turn in unison with the shaft I, and the outer arms 34 and 35 likewisc do not turn in unison with the shaft l.

The gear 32 meshes with a fibre gear 39 which is suitably connected to a disk 40 by means of a nave Ma. 'I'he relative movement between said gears 32 and 39 is slight, so that they always remain in mesh.

As shown in Fig. 5, the edge of disk 48 abuts the adjacent edge of the member 33. As shown in Fig. 3, the arms 3'4 and 35 have their lower ends connected by means of a pin 4| which passes through an intermediate link member' sented in Figure '1.

Likewise, and as shown in Fig. 3, the arms 34 and 35 have a pivot member 43 on which the fibre gear 39 and the disk 40 are turnably mounted. The plate 40 is eccentrically mounted with respect to its pivot pin 43 and, since the smooth periphery of disk 40 contacts with the smooth periphery of the ring 33, the fibre gear 39 drives the disk 40 and causes up and down movement of the arms 34 and 35. The up and down movement of the arms^34 and 35 is guided by means of the guide blocks 34a and 35a.

As is obvious from Figs. 7, 14, and 15, pin 4| 42 which is represerves for connecting the arms 34 and 35 with latter carries a head which is revolvably sup-` ported in between the arms 34 and 35 by means of bolt 86. Bolt 84 carries an adjustment nut 81 which, together with bolt 84, extends through a slot 88 outside of the frame F. 89 designates a washer and a spring which is wound around bolt 84 and abuts with one end against the extension'42 and with its other end against the head 85 of bolt 84.

The link member 42 is pivotally connected at 43 to a horizontally movable member 44 and is also pivotally connected at 45 to an arm 46 which is pivotally connected by a pin 41 to the frame F of the machine. The member 46 is shaped like a fork, and the upper ends |44 of the member 46 straddle the regulating screw 41a and also straddle the block 48 which is threaded upon the screw 41a. The block 48 has lugs which abut the members |44. When this screw 41a is turned by means of the head 49, the block 48 is forced inwardly or outwardly, thus turning arm 46 and regulating the position of member 42 which also regulates the position of the member 44. An-

A pin 50 passes through the block 48 and this pin 50 is connected to the head 5| of the regulating device which is connected to the frame of the machine by means of suitable screws 52, so that the block 48 can move in and out but cannot turn.

The head 49 has a toothed wheel 53 connected thereto. A click 54 is pivotally mounted upon a screw 55 and this click has a tooth 56 which is held against the toothed wheel 53 by means of a tension spring 51. The tooth 56 also serves as the index for a scale which is marked upon the tapered end of the member 49.

The Work-holder 4 is tilted in the upward direction by means of a tension spring 60, the inner end of which is connected to the frame of the machine as shown in Fig. 8. The outer end of the tension spring 60 is connected to an eyemember 6| which is pivotally connected at 62 to a threaded member 63 upon which a reg-ulating head 64 is provided. Hence, the tension of the spring 68 tends to hold the work-holder 4 yieldingly in its upper position, and this upper position can be regulated by turning the member 64. An auxiliary adjustable stop 65 is provided in order to limit the upward tilting of the workholder 4.

As shown in Fig. 8, the member 44 has a compression spring 61 mounted upon it, and the inner end of this compression spring 61 abuts a sleeve 69 which is adjustably mounted upon the member 44. The sleeve 69 is integral with a clamping coller 66 so that y slide along and be clamped on member 44 in any desired position in order to regulate the compression of spring 61. When member 44'is pushed outwards by the arms 34 and 35, it is forced against the corresponding portion of the work-holder 4 so as to downwardly tilt the work-holder with reference to the pivot 5.

In this particular embodiment, the gears 39 and 32 have a two to one ratio so that the gear 39 turns once for every two revolutions of the gear 32. The gear 32 turns once with every complete oscillation of the needle. Hence, the work-holder 4v is depressed or tilted in the counterclockwise direction once -for each two complete oscillations of the needle shaft, If any other desired ratio in the skipping of the layers of fabric is desired, the ratio between the gears 39 and 32 can be changed,

The arms 34 and 35 move downwardly in order to turn the member 42 with reference to the pivot 45 and to thereby actuate the member 44 outwardly. The machine is particularly designed for securing a hand-sewn effect upon a hem which has three layers A, B, and C. Every time a stitch ls made, the thread is visible on the outside face of the layer A. In order to secure the imitation of hand-sewing, it is desirable to skip the markings by having the stitch skip the layer A in, any predetermined manner.

Hence, the object of tilting the work-holder is to cause the needle to skip the layer A in any desired series as, for example, one to two, one to three etc.

For example, Fig. 10 shows the needle passing through the three layers of the hem, and Fig. 1l shows hcw the needle skips or misses the layer A.

The cloth is prevented from moving up too far under the action of the rib 22 by means of a finger 10 which is mounted upon a pivot pin 1|b and which is forced downwards by means of a torsion spring 12. The pin 1lb is mounted upon the extension 1| of an arm 1|a.

the member 69 can" Blind stitch sewing machines according to the present invention and having provisions for ad. justing the so-called intervals produce loose, soft, and good looking seams which look as if they had been made by hand. The reason for this is -'that the lower layer need not be stitched into at every revolution but only at every other revolution.

In the embodiment of the present invention illustrated in Figs. 16 to 25, inclusive, |0| designates the fra-me of the machine, |02 the driving pulley, and |03 the main drive shaft. To the shaft |03, an eccentric |04 is connected comprising a lever |05 to which the main drive rod |06 is linked. To rod |06, the oscillating shaft ||2 is linked by means of levers |01, |06.4 |09, ||0, and An intermediary v lever ||4 connected with rod I2 transmits the movements of rod ||2 to the device for bending the cloth, the node forming element ||5.l As is more clearly shown iny Fig. 17, the latter moves up and down in the slide |6. is a stationary pressing plate which has l an opening through which element ||5 extends.

before abutting the layer I0 and also bending up layer ||9 whichrests on layer H6. Needle |20, which is guided by the stitch plate |2|, enters layer I9 as shown in Figs.'1'6 and 17 at a revolution of the main |03 at which the layers of cloth are lifted by the node forming element |15. At the next following complete revolution of main shaft |03, needle |20 enters layer ||3 because node forming element ||5 is then lifted further upwards. Pressing plate ||1 is movably connected with the slide ||6, whereas needle |20 and stitch plate |2| are connected with the head of the frame of the machine in a manner which is not shown because this does not form part of the present invention and is well known in the art. To the bolt |05 which links lever |05 to lever |06, a guide lever |22 is movably connected as is particularly shown in Fig. 20. As is obvious from Fig. 20 lever |22 is linked to link-pin |05 which isucommon to levers |05 and |06 so that the axis of pin |05 is guided on an arc which arc, at normal stroke of the eccentric |04, is an almost straight, vertical line. Lever |23 is movably connected to link bolt |01' which interconnects levers |01 and |03. Lever |23 guides the end of lever |01 on a. substantially straight path. To lever |06, control lever |24 is movably connected which is driven by means of shaft |03 to which it is operatively connected by means of the tooth wheels |25, |26, and |21. As is shown in Fig. 21. wheel |21 is mounted to the short shaft |28 which carries at its front side a slide |23 which, by means of a crank pin |30 and a crossl head |3| which is reciprocatingly moved in the slide |32 by means of said pin |30, causes an oscillating movement of lever |24- The shaft stump |28, tooth wheel |21, slide |23, and pin |30 together form a crank drive, the active radius of which can be varied by movement of pin |30 by means of slide |26 from the position in which the axis of pin |30 coincides with the axis of shaft |28 into a position in which pin |30 is furtherest away from shaft |28. Such movement is carried out by rotating wheel |33 which is rotatable about the shaft |28 and comprises an arcuate slot |33.

Slot |33' abuttinglycooperates with bolt |34v which is pushed toward or from shaft |28 when wheel |33 and with it slot |33 is rotated. Bolt |34 thereby moves in the slot |35 and, being con- 'nccted with slide |23, also moves said slide in a reciprocating manner. The distance of pin |30 from shaft |28 can be set by tightening nut |36, which nut must be loosened before adjusting in th slide frame |3| and forms a cross'head therewith v which is. reciprocatingly movable in slide frame |32. The circular movement 0f crank .pin |30 is thus transmitted into a recipror eating motion of part |3|and the-.control rod |24 connected thereto.

control mechanism protrudes from the frame IIIv of the machine and. is housed in a -casing |30 having a cover |36', whichcasing is' mounted to the frame and.is easily accessible.

In the machine-.according to Figs'.v i6; tev ,2 1.,

inclusive, the fulcrurn of-lever |24 -is moved in a straight line at everyother revolution of the main shaft of the sewing machineas far tothe l left as it is'movedto the right at every fourth revolution of the main shaft.

In the machine shownin Figs. 2.2 and23,.the

operation issinipliiieriy in thiscase the fulcrum f of lever |24 swings non a circular path vand an only approximately straight motion `is created. This, however, is suiiicient for practical purposes. In the machine according to Figs. 22 and 23, the slide |32 of the machine vaccording to Figs. 20 and 21 is replaced bythe pendulum |32 which swings about fulcrum |22' and which imparts a reciprocating motion to control lever |24. Crank pin |30 is guided in-slide` |.3.| which is Vdirectly connected with pendulum |32. -The tooth wheel |21 is Vdriven by a tooth wheel`|26 which is operated by atooth wheel-.which is-A connected to the main drive shaft. |03 and corresponds vto wheel |25 in Fig. 20. 4The speedratio of the transmission fromv shaft |03 toshaft |28..is one to four. Lever |06 is in v its medium position at.'-

the first revolution of the machinevand in the lever |06, the node forming. element reaches its normal elevation.v At the next following, i. e., second revolutionof the 4main shaft |03, rlever |06 reaches its left interval position in whichv in Figs. 24 and 25, the ratio of `the speed trans`- mission lbetween tooth-wheel |25' which corresponds to wheel |25 in Figs. 20 to 23-and wheel |21 which corresponds to wheel |21 in Figures 20 to 23 is only one to two. By meansof control |24', lever |06vis moved from the normal medium moment in which theeocentric |04 is in its I lower dead center position.`V At-thisposition. of f position into interval position atv left .and back to medium positionv and again to left interval position. Therefore, the interval 'cannot be changed within-.suena wide range as is the case in the machine shown in Figs.' 20..t0 23 but within a limited range only. The modificationof the present invention illustrated `in Figures 24 and 25 is further simplied'in'that a slidel |32` as in Figure 20 or a swing member |32 as per Figure sewn is done in accordance with the thickness of said material.

While I believe the above described embodiments of my invention to be preferred embodiments, I wish it to be understood that I do not desire to be limited to the exact details of design and construction shown and described, for "obvious modications will occur to a person skilled in the art.

What I claim is:

l. A blind-stitch sewing machine comprising a node forming element for forming a bight in the materiall to be sewn, driving means connected with said element and adapted to impart a reciprocating motion to said element, said driving means comprising a link-lever, a control lever linked to a point of said link-lever which point is intermediary the two ends of said link-lever and which forms a fulcrum about which said linklever swings, operating means connected with said control lever for imparting a substantially reciprocating motion to said control lever, adjusting means connected with said operating means for changing the stroke of the reciprocating motion of said control lever and thereby changing the position of said fulcrum and the stroke of the reciprocating motion of said node forming element. a

2. A blind-stitch sewing machine comprising a node forming element for forming a bight in the materials to be sewn, driving means connected with said element andvadapted to impart a reciprocating motion to said element, said driving means comprising a link-lver which moves substantially reciprocatingly infsubstantiallythe direction of its longitudinal'extension, a control lever linked with one end to a fulcrum of said link-lever which fulcrum is situated intermediary the two ends of said link-lever, a cross head linked to the other-end of said control lever, said cross head being iadapted to reciprocatingly move in a direction which is substantially perpendicular to the direction of the reciprocating motion of said link-lever.

3. A blind-stitch sewing machine comprising a main drive shaft, a node forming element for forming a bight in the materials to be sewn, driving means connected with said element and adapted to impart a swinging motion to said element, said driving means comprising a linklever which is adapted to move substantially reciprocatingly in substantially the direction of its longitudinal extension, said link-lever comprising a fulcrum which is situated intermediary the two ends of said link-lever, a control lever linked with one end to said fulcrum, a cross head linked to the other end of said control lever, a gearwheel having a crank-pin connected thereto which pin is movably connected with said cross head and which reciprocatingly moves said cross head in a direction which is substantially perpendicular to the direction of the reciprocating motion of said link-lever, and a train of toothed wheels connecting said gear-wheel and said main drive shaft.

4. A blind-stitch sewing machine comprising a main drive shaft, a node forming element for forming a bight in the material to be sewn, driving means connected with said element and adapted to impart a swinging motion to said element, said driving means comprising a linklever which is adapted to move substantially reciprocatingly in substantially the direction of its longitudinal extension, said link-lever comprising a fulcrum which is situated intermediary the "`\L\ v two ends o1'. said link-lever, a control lever linked with one erfd said fulcrum, a cross head linked toithe othersend of said control lever, a gearwheel having 'a crank-pin connected thereto which pintis movably connected with said cross head land which reciprocatingly moves said cross head in a direction which is substantially perpendicular` to the direction of the reciprocating 'motion of said` link-lever, and a train of toothed wheels connecting said gear-wheel and said main drive shaftfsaid train of wheels effecting a speed reduction of said gear-wheel with respect to the speed o f said main drive shaft.

5. A blind-stitch sewing machine lvcomprising a main drive shaft, a node forming element for forming a bight in the material to be sewn, driving means connected with said element and adapted to impart a swinging motion to said element, said driving means comprising a linklever which is adapted to move substantially reciprocatingly in substantially the direction of its longitudinal extension, said link-lever comprising a fulcrum which is situated intermediary the two ends of said link-lever, a control lever linked with one end to said fulcrum, a cross head linked to the other end of said control lever, a gearwheel having a crank-pin connected thereto, which pin is movably connected with said cross head and which reciprocatingly moves said cross head in a direction which is substantially perpendicular to the direction of the reciprocating motion of said link-lever, and a train of toothed wheels connecting said gear-wheel and said main drive shaft, said train of wheels effecting a speed reduction of one to four of said gear-wheel with respect to the speed of said main drive shaft.

6. A blind-stitch sewing machine comprising a main drive shaft, a node forming element for forming a bight in the materials to be sewn, driving means connecting said main drive shaft and said element for imparting a swinging motion thereto and comprising a main link-lever adapted to reciprocatingly move substantially in the direction of its longitudinal axis, a parallel guide means comprising a member adapted to reciprocatingly move substantially parallel to the longitudinal axis of said main link-lever, said main link-lever having two ends one of which is movably connected with said parallel guide means, another link-lever also having two ends one of which is movably connected with that end of said main link-lever which is not connected with said guide means, the other end of said other link-lever being movably connected with said parallel guide means, whereby one end of said main link-lever and one end of said other linklever are guided to move substantially parallel to the longitudinal axis oi'. said main link-lever.

7. A blind-stitch sewing machine comprising a frame, a node forming element for forming a bight in the materials to be sewn, driving means connected with said element and adapted to impart a reciprocating mo-tion to said element, said driving means comprising a link-lever which moves substantially reciprocatingly in substantially the direction of its longitudinal extension, a control lever movably linked with one end to said link-lever at a point which is situated intermediary the two ends of said link-lever, an eccentric having a disc and a rod, said disc containing a cross head having a pin which is movably connected to the other end of said control lever, said rod being movably connected to said frame and being adapted to swing in a direction which is substantially perpendicular to the direction of the reciprocating motion of said linklever.

8. A blind-stitch sewing machine comprising a main drive shaft, a node forming element for forming a bight in the materials to be sewn, driving means connected with said element and adapted to impart a swinging motion to said element, said driving means comprising a linklever which is adapted to move substantially reciprocatingly in substantially the direction of its longitudinal extension, said link-lever comprising a fulcrum which is situated intermediary the two ends of said link-lever, a control lever linked with one end to said fulcrum, a slide carrying a pin which is movably connected with the other end of said control lever, a gear-wheel having a guide for carrying said slide, whereby, upon rotation of said gear-wheel, said control lever is moved in a direction which is substantially perpendicular to the direction ofv the reciprocating motion of said link-lever, and a train of toothed wheels connecting said gear-wheel and said main drive shaft.

9. A blind-stitch sewing machine comprising a main drive shaft, a node forming element for forming a bight in the materials to be sewn, driving means connected with said element and adapted to impart a swinging motion to said element, said driving means comprising a link-lever which is adapted to move substantially reciprocatingly in substantially the direction of its longitudinal extension, said link-lever comprising a.

`iulcrum which is situated intermediary the two ends of said link-lever, a control lever linked with one end to said fulcrum, a slide carrying a pin which is movably connected with the other end of said control lever, a gear-wheel having a. guide for carrying said slide, whereby, upon rotation of said gear-wheel, said control lever is moved in a direction which is substantially perpendicular to the direction of the reciprocating motion of said link-lever, and a train of toothed Wheels connecting said gear-wheel and said main drive shaft, said train of wheels eiecting a speed reduction of two to one of said gear-Wheel with respect to the speed of said main drive shaft.

OSKAR S'I'ROBEL. 

